Quite the Excitable Young Lady
by taylorpotato
Summary: Joan and Shirley have been best friends since primary school. Just friends. Because Joan likes boys. Shirley's never told Joan about her own preferences. One night, Joan and Shirley get drunk off a bottle of Mycroft's wine and they have a discussion about self-pleasure. Femslash follows in short order. Teen!lock and Genderswap, because this is my party and I'll AU if I want to.


_Fair warning: underage sex. Yep. Two fifteen year olds, gettin it on together. Don't read if that's not something you're into. Voyeurism. Exhibitionism. Masturbation. Finger fucking. Drunk sex. Happy times. Also, genderswap means this is all girl on girl so... yeah. Go forth and enjoy :)_

* * *

Joan and Shirley met on the first day of primary school. It was Shirley's birthday. She wore a little hat and had a pink balloon. Sadly, during lunch time, one of the boys stole said balloon and sat on it until it popped. She yelled at him. Told him his mother clearly liked his older brothers better, judging by the state of his lunch box. When he slapped Shirley, Joan rushed over, screaming, "you're never allowed to hit girls!" and shoved him to the ground.

The two girls quickly became inseparable.

Both odd in their own little ways. Joan often wore fuzzy jumpers that were much too big for her small body and was frightfully obsessed with the idea of becoming a nurse. Shirley had a habit of dissecting animal corpses she found in the park, and instead of making baking soda volcanoes, often created dangerous reactions with the class chemistry set. Once she even caused a fire.

As they grew older, the contrasts became more apparent. Joan stayed fairly short, while Shirley shot up like a beanpole. They'd both been skinny children. But around twelve or thirteen, Joan grew much wider at the hips, giving her a pleasant roundness to compliment her heart-shaped face and honey blonde hair. Shirley stayed angular and bone-thin. She refused to grow out her dark curls because they were bothersome. She kept them short to avoid dealing with them.

Most of the other girls started to titter about boys. Joan and Shirley would climb onto the roof at the Holmes Estate to star gaze. They would eat entire pizzas and stay up all night watching Dr. Who. They would go swimming. They would get muddy collecting frogs for Shirley to observe and document. They were a self-contained world of two.

But then things began to change.

Joan started putting on lip-gloss, and wearing cute little dresses instead of oversized jumpers. And the boys _noticed_.

Really, it was because Joan had breasts. Or at least, that's what Shirley suspected. But the boys would stare at her chest. They would stammer when Joan addressed them. Because really, her breasts were quite large for a fifteen year old. Shirley wasn't jealous. Not really. In fact, she could understand the pleasing aesthetic of Joan's body. She just didn't like the idea of _sharing_.

The real problems began when Sam Sawyer started making the moony eyes. Two years older. Generally considered to be quite handsome. Good at football. Also interested in becoming a doctor.

No mater how much Shirley went on about how utterly boring Sam was, Joan didn't seem to listen. Because when he asked her out to the cinema, she said yes. Shirley knew what people did in movie theaters. They kissed and groped each other. She hated the idea of Sam's large, calloused hands touching Joan's soft, lightly tanned skin.

She sulked the entire week leading up to the date.

It was sheer, dumb luck that she managed to fall off her bike on the way to school the day of the cinema rendezvous. When she limped into class twenty minutes late, all scraped, tousled, and bleeding Joan's pale blue eyes went wide and frantic. She all but dragged Shirley to the nurse's office, and insisted on playing caretaker after the school day ended.

The scrapes weren't all that bad. But perhaps Shirley exaggerated just a little bit. Because when Joan's mobile rang at 18:00, she didn't answer it. She missed her date in order to spend the entire evening fussing over Shirley.

It was glorious.

* * *

The problem didn't end with Sam. After Sam, there was Luke—a delightfully boring boy that had a dog and a skateboard. Shirley had to convince Mycroft to take both her and Joan to Cornwall on the weekend Luke's parents were going out of town. Joan didn't seem to catch on. She was too excited about their mini-holiday. They ate ice cream, walked about the beach, and had a wonderful time doing nothing.

After Luke there was Charles—a dodgy character with an off-center nose and a rather unsavory way of speaking. He asked Joan to a party, and Shirley tagged along, because she feared for Joan's safety. Charles just kept pouring the drinks into Joan until her cheeks were flushed, and she couldn't stop giggling. Shirley grabbed a hold of Joan's hand while Charles left to get them more alcohol, and she refused to let go for the rest of the night. She called them a cab, and let Joan sleep in one of the guest rooms at the Holmes Estate.

The next day, Joan didn't remember enough to be cross.

But these were all band-aid solutions. Shirley still hadn't solved the root problem. Eventually Joan would find a boy that she really liked. Perhaps a boy that she liked so much, it would make her tell Shirley to piss off. Leave her alone.

And the thought made Shirley feel ill.

Because it was always the two of them. They were halves of a whole. And if she lost Joan, she'd feel empty and alone.

Not to mention the odd, prickling heat that had turned up. It coursed through Shirley every time Joan touched her. Looked at her a certain way. Almost uncomfortable, but familiar enough to embrace. Joan made her stomach turn somersaults in the most pleasant way… But no. She shouldn't feel like that. It wasn't normal, was it?

Shirley had never liked boys all that much. She could run around and play football with them. Or talk about insects and gross things, or enjoy the same horror movies as they did. But she wasn't quite one of them. They never really accepted her—even if she could beat most of them in a fight—because she was a girl.

However, she was equally bad at being around girls that weren't Joan. They all thought she was odd. They'd catch her staring at them and whisper _freak._ Because Shirley wore boy's trousers, and had no breasts to speak of. If her voice weren't so high, you might confuse her for something else. Sometimes people in department stores addressed her as, "sir" before they heard her speak. It was oddly thrilling whenever it happened.

She'd done her research. Looked at pictures of naked men and erect penises on the Internet. None of it did much for her. But when Joan made her watch old Star Trek reruns, Shirley found herself mesmerized by Uhura, and she'd get an odd tingling between her legs.

Once she'd watched a porn video, with two women licking each other, and she'd gotten slick and achy. She hadn't known exactly what to do. But she locked the door to her bedroom, lay down on her bed, and stripped off her trousers and pants. She slid her hand down between her legs, over that course patch of hair, down to where her skin was warm and a little bit slippery. She slid a finger inside herself and trembled slightly at the sensation. It was odd. Fine. But not quite what she wanted.

The ticket, it seemed, was to rub circles around the little nub at the top of the slit. Not really direct contact. More just touching around the edges. Gentle. It hurt if she pressed very hard. But when she got the light pressure, and steady rhythm right… _god. _It almost tickled. But she never wanted it to end.

A strange sort of tension built inside her. Almost more than she could stand, but not quite enough. This was what everybody talked about. The main event. Getting off.

Except, Shirley didn't. Well, not at first. She rubbed at herself for a good twenty minutes, the tingling changing in intensity and pleasantness, but never quite getting to a lofty point of no return.

Then she thought about Joan. Wondered if she'd ever touched herself. It felt like all the blood rushed to the surface of her skin, and then downward. It made her throb. Made her breath catch. Her mouth fell open and she let out a series of tiny panting noises.

She decided to get her other hand in on the fun, and dipped her finger down towards her entrance. She was almost shocked by the amount of lubrication and wetness that had developed there. She slid inside once again, and this time it felt much better. She kept rubbing at the little nub and began to experimentally slide her index finger in and out of herself.

The pressure built. Too much. She couldn't take it. Then, all of a sudden, it released. She felt her muscles contract around her finger. She shuddered and gasped as the pleasure licked across her nerve endings. She let her hands fall down to her sides. She felt wonderful, boneless and sticky.

She tried not to dwell on the fact that thinking about Joan had pushed her over the edge. It didn't seem proper to use one's friends that way, even if it was in a secret mental playground.

But the next time she saw Joan, she felt an odd throb, in her throat, in her chest, _in_ her.

God. She wanted her. So badly. But she could never let on. Because Joan liked boys. And if she knew what Shirley liked, well… she might run away screaming.

* * *

Of course, large secrets always find a way out into the world. There isn't a worse feeling that bottling something up and trying to hide it. It's like pushing a cup full of air under the water. It always fights to get back to the surface.

Shirley should have known better.

But summer came, and they were left with very little to do. She and Joan often stayed over each other's houses to hold the boredom at bay. And one night, Shirley managed to steal a bottle of wine from Mycroft's secret stash up in the attic.

Shirley had never been drunk before. She'd been to few parties, and any time she'd gone it was mostly to look out for Joan. She'd only ever sipped beer to keep up appearances. She found the taste of most alcohols vaguely repulsive.

But Joan said she wanted to drink, so of course, Shirley said, _yes__ Joan. Let me go nick one of Mycroft's bottles, he's got plenty to spare._

They locked the door to Shirley's bedroom and sat on her queen-sized mattress, passing the bottle of wine back and forth. They turned off the overhead lamps so it was just the blinking strand of Christmas lights that Shirley had strung along the top of the walls, casting a soft, pleasant illumination down on them.

Her room was fairly large. Much larger than any bedroom at the Watson household. But it was also rather empty. Just a desk, a fish tank, and some bookshelves. Her closet was full of boy's clothes. Dress trousers, cotton button downs, blazers and the sports bras she often wore to press her nearly non-existent breasts down flat.

That particular night, she had on her favorite silk shirt—a dark purple, utterly skin-hugging affair. Joan's gaze would always linger on Shirley's lithe body for a few seconds longer than normal when she wore it.

And Joan, well, Joan was in a ridiculously florid cotton dress, with spaghetti straps, and no bra. The Estate had central air. She could see Joan's nipples, hard from the cool of the room. She tried not to stare, but it became more difficult with each progressive sip of wine.

The taste wasn't so awful. It was warm, and slightly woody. It burned pleasantly. Made everything welcoming and fuzzy at the edges. Joan's cheeks flushed. She giggled.

"I was talking to Sally Donovan the other day," she tittered, "and she said she lost _it_."

"Lost what?" Shirley rolled her eyes, annoyed that they were wasting breath talking about such a boring person. Or maybe she was just slightly bitter.

Once she and Sally had almost kissed. They'd been on a school trip. They both got separated from the group at an art museum. Instead of trying to find everybody else, they'd decided to skive off and smoke a few cigarettes on the roof. They had a surprisingly pleasant conversation about forensics. On the way back down the stairs, Sally's hand had brushed against Shirley's. Nobody around. They paused in the middle of the stairwell, just staring at each other. Their faces had been so close. Shirley still remembered how Sally had looked. Light streaming in through the window, making her frizzy brown hair look like an angel's halo. They'd leaned together. Breathed the same air. Then of course, Sally panicked and pulled away. They'd hated each other ever since.

"She lost her virginity," Joan whispered breathily, "with Anderson."

"Poor girl," Shirley snorted, snapping back to the moment.

"Why do you say that? She's fifteen, she's not that young."

"Of course not. Just Anderson's a git, and I bet he had no idea what he was doing. It probably hurt something awful."

"Oh come on, I bet it wasn't that bad," Joan huffed.

"Boys, in general, are idiots. What makes you think they'd be any smarter about sex than they are about geometry."

"Well for one thing, I think sex is a lot less complicated."

Shirley just raised her eyebrows. "Big words for somebody that's never had it."

"It's not like you know any more about it than I do." Joan took a large gulp of wine.

"I'd say that's probably arguable. Have you ever masturbated before?"

Joan's cheeks flushed bright red and she looked away.

"I'll take that as a yes," Shirley giggled. "Did you get off?"

"I… no," Joan said quietly.

"What did you do?" Shirley shifted slightly, trying to ignore the way her blood raced around. Pooling down between her legs, making her start to ache.

"I dunno, I just… I stuck my fingers in and… frankly I don't see what all the fuss is about. It didn't feel that good."

"Were you wet?"

"Kind of," Joan bit her lip.

"It's more about your clitoris than anything," Shirley reached out for the wine. "With all those medical texts you study, I'd have thought you'd know that."

Joan chose not to say anything. Instead she stared up at the ceiling. Shirley allowed her eyes to linger on Joan's chest for a moment before continuing.

"Your clit it that little bump at the top of the slit. You don't really touch it, just kind of rub circles around it."

Joan squirmed slightly. Shirley wondered if she ached too. Just talking about it with her was nearly too much to handle. She had to resist the urge to trail her hand down between her legs and start rubbing herself through the fabric of her trousers. Her pants were already sticky. She could feel it.

"I dunno," Joan said after a moment holding her hand out for the wine. Shirley handed it over and watched Joan take a long gulp. "Are you sure? Any time I've touched there it just… well it hurt."

"You probably pressed to hard," Shirley shrugged.

"Well, it either hurt, or I didn't really feel much of anything," Joan mumbled. "I dunno. You've been to my house. Not like I get a whole lot of opportunity now that Harry's back for the summer and we have to share a room. She gets angry when I lock the door, and…" Joan waved her hand obscurely.

Shirley's heart thumped in her chest. Intellectually, she knew she only felt brave because of the alcohol. Consequences seemed so far off and obscure. And Joan was right _there_. This was the sort of moment she'd always dreamed about wasn't it? Her one chance. If she didn't take it, maybe they'd never talk about this again.

"I could um, you know… I could show you… if you'd like," she said softly. In a way that she hoped seemed nonchalant.

Joan didn't leap off the bed and scream _freak_. No. Instead she just stared at Shirley for a few moments.

"Really?" She asked in a strange breathless voice.

"Sure, I mean… you've got to learn sometime, right?"

The corners of Joan's mouth twitched upwards slightly. "This is weird isn't it? Do people even do things like this?"

"Who cares?" Shirley dared a smile.

Joan seemed to mull it over for a moment. She finished off the wine and set the bottle on the side of the bed. Then she sat with her legs sprawled out to either side, dress bunched halfway up her thighs, and she nodded.

"Ok, show me."

Shirley sat up a little straighter, placed a hand about halfway down her leg and slowly trailed it upward. She could feel Joan's gaze burning into her. She couldn't look up. No. If she looked Joan in the eyes at that moment, Joan might _see. _All the things Shirley tried to bury might spill out.

So she carefully feathered her fingers up her thigh until her palm rested against her belt buckle. She cupped herself. Felt the warmth radiating off her sex. She made a gentle circle with her index finger, just teasing. She always found she could take a bit more pressure when her clothes were in the way.

But the point of this was to _show_ Joan what to do. And she couldn't very well see what was going on through the layers. So Shirley unbuckled her belt and slid it off. Unzipped her trousers, pulled them down and wriggled out of them.

Her white cotton pants had an obvious wet spot. Joan made a small noise. Almost like a gasp. Shirley didn't dare look upwards. She grasped the elastic waistband and slid her pants off as well, tossing them aside.

She'd never felt quite so exposed. God. How exciting. A little spike of heat shot through her. She took a shuddery little breath and let her index finger dip into the slickness between the lips of her pussy.

"A lot of the time," she said quietly, "it helps it you keep wetting your finger. Makes it feel better."

She stretched her long, thin legs wide, giving Joan quite a view. With one hand, she spread herself, and pulled upwards slightly. Exposing her clit just enough. She wetted her finger once more for good measure, then she began to trace gentle, meandering circles around the bump of nerve endings, just barely grazing against it. Her mouth fell open. She made a small whining noise.

"Oh," Joan murmured. "That um… wow…"

Shirley let her finger dip down, sliding inside herself once, twice, so Joan could see, then returned to the circling motions. God. She was dripping. She'd never been so wet. Something about being _watched_. Having Joan right there…

There was a rustling sound. The mattress springs creaked.

Shirley looked up just in time to see Joan sliding out of her knickers. They were a light purple. Lace. It sent a sharp pang of arousal through Shirley's entire body. Joan's hand wandered up underneath her dress.

"Can I… can I see?" Shirley said with a shaky voice.

Joan nodded, pulling up her dress, letting it bunch around her hips to give Shirley a good view.

Her pubic hair was soft and golden. The lips of her pussy were smaller than Shirley's. A dusky pink. Shirley had the sudden urge to lean forward and _lick it_. But she didn't. No. Whatever they were doing here was a fragile suspension of reality. She mustn't do anything to shatter such a perfect moment.

Joan's fingers weren't nearly as long as Shirley's. They were short, and a tad bit pudgy. Adorable. She slowly slid her middle finger inside herself. Shirley bit back a moan. She'd never seen anything so beautiful. So fucking enticing.

She watched, the near painful tension starting to build as Joan trailed her finger up to the top of the slit, and made a small motion. She let out a breathy noise. Then she picked up the speed. Much too fast. Too rough. She winced.

"Not like that," Shirley said, "you've got to be gentle. There's no rush."

Joan paused. Then she started again. A bit slower. She squirmed slightly. They stayed silent for a minute or two. Shirley was far too close to the edge. About to go over at any moment. But Joan… Joan just looked increasingly frustrated.

She stopped all together, letting her hands fall.

"It's no good," she said in a strained, exasperated tone, "I can't. God… it looks like it feels so nice when you do it but I…" she trailed off.

Really, it was a heat of the moment decision. The kind of thing Shirley never dreamed she'd have the guts to do. But she stopped touching herself and took a deep breath.

"Do you want me to… you know… I could…" she was sweating. She'd never felt so hot. Or so fucking terrified. Joan was looking at her. Shit. She shouldn't have said it. She'd crossed the line. Joan had to _know_. She had to know everything.

"Would you?" Joan asked quietly.

A strange combination of anxiety and relief flooded through Shirley. She nodded. "Come over here."

Joan crawled over, kneeling in front of her. Waiting. Eyes wide. Pupils stretched out and dark.

"You'll um… I only know what to do from this angle. Perhaps… sit against me?"

Joan nodded. Then she turned around. Leaned her back against Shirley's chest. God. Joan could probably feel how wildly Shirley's heart was beating. Gently, carefully, she pulled the folds of Joan's dress upwards. Her breath hitched as Shirley trailed long fingers up the soft skin of Joan's inner thighs.

"Just relax," she barely whispered.

_Fuck._

This was happening. Actually happening. Her head spun. She pressed her hand over Joan's crotch reverently. It was slick. Burning hot. Joan shifted her hips slightly. Moving upward, almost imperceptibly, into Shirley's touch.

She started at the bottom, trailing her middle finger up the wet crease. Joan shuddered against her. Her hands should have been shaking, but by some miracle, they remained steady.

Really, Joan's pussy felt a lot like hers did. The differences were subtle. Everything was a bit smaller. Plumper. But she found Joan's clit, just barely brushed against it, and began the same circling motion she usually enjoyed,

It was different, performing the action without being able to feel it. Being able to gauge how much pressure to use. She kept on the safe side of light. Almost tickling. Joan let out a small moan, so Shirley was obviously doing something right. Joan's head fell back against Shirley's shoulder. Lips parted. Eyes closed.

Shirley kept up the steady, insistent stimulation, occasionally giving a bit more, or a bit less, until Joan started to squirm and spread her legs wider.

With her other hand, Shirley carefully teased a finger across all the slick skin, dipping into Joan slightly before retreating. Joan was quite thoroughly aroused. It made Shirley's entire body ache, to know she was at least partly the cause for Joan's excitement. Entirely responsible for the pleasure she must be feeling.

Her courage bolstered, she slowly slipped a finger all the way into the tight, dripping heat of Joan's cunt. Joan let out a breathy, shocked sound.

"Oh god, Shirley," she whispered.

No longer thinking about waking up tomorrow to a ruined friendship, Shirley pressed a small kiss into the tender skin of Joan's neck. Began to slide her finger in and out of the incredibly slick, velvety warmth of Joan's pussy. Joan shuddered and panted, canting her hips up, meeting the motions of Shirley's fingers.

Must be getting close.

Somehow, she just kept getting wetter and wetter. Shirley dipped her other finger down, slicking it, and returned to stimulating Joan's clit. She was at the point where _more_ wouldn't hurt. So she became a bit bolder with her motions. She occasionally slid the pad of her finger directly across the tense little bundle of nerve endings. Feather light. Just enough.

Joan _squeaked_.

It shouldn't have been sexy. But fuck all. It was. It was the hottest goddamned thing Shirley had ever heard.

Suddenly Joan's hand reached upwards and tangled in Shirley's curls. Joan strained upwards, and pulled Shirley down, mashing their lips together. The angle was awkward. Their teeth clicked by accident a few times. But neither of them seemed to care. Their tongues swirled together, clutched at each other. It felt like drowning. It felt like burning alive.

Shirley got lost in it. But not lost enough to stop what she was doing. Joan began to quiver. She moaned into Shirley's mouth. And then she tensed. Her hips jerked upwards. Shirley felt Joan's internal muscles contract around her finger. Several times. A series of delirious rhythmic spasms. She continued a light stimulation, slowly bringing Joan down, until she went limp and breathless.

A pleasant haze still lingered in the room. The smell of sex and wine. Shirley felt like an over-tightened violin string. Ready to snap at any moment from the sheer intensity of her arousal. But she didn't want to move. She'd rather have Joan rest against her and go on in this state of ridiculous need forever.

"That was…" Joan gasped, "Jesus Christ that was fantastic."

"Glad you enjoyed it," Shirley chuckled lightly.

"Did you… you still need to get off," Joan bit her lip and looked up at Shirley.

Shirley shrugged. "It's ok. I could wait."

"No," Joan breathed, "let me help you."

"You don't have to—"

"Want to," Joan murmured.

She turned around and pushed Shirley back onto the bed. Then climbed on top of her and began to kiss her again. Shirley felt like she might die at any moment. Her entire body was a mess of throbbing want.

Joan's dress road up, and she pressed her naked thigh against Shirley's cunt. Shirley squirmed and writhed against the contact, humping Joan's leg. If Joan minded, she didn't say anything. She kept right on trying to devour Shirley's mouth.

_Oh god_.

Shirley felt the tension start to gather inside her. She was already so on edge. She rutted frantically against Joan's offered skin. It became slick with Shirley's arousal. Too much. Not enough. Oh dear. Oh fuck.

"_Joan,_" it came out as a soft, strangled whine. And Shirley shuddered. Let the wave of intense, tingling heat devour her.

They rolled onto their sides. Tangled up in each other. They must have been a sight. Shirley naked from the waist down, all thin pale legs and sticky thighs. Joan almost completely dressed, with messy hair and a flushed face.

Neither of them spoke. Just breathed heavily. Synchronized. Eventually Shirley sat up to pull down the duvet. Joan giggled nervously as she peeled off her dress, exposing so much more bare skin, plump breasts sitting high and unencumbered on her chest. Shirley may or may not have licked her lips at the sight. She unbuttoned her shirt and slipped off the tight grey sports bra she usually wore underneath it.

They climbed under the duvet, and got throughly tangled up in each other—a mess of angular limbs and soft curves. It was thrilling in a whole new way. Shirley was still wet She couldn't tell if it was residual, or spurred on by the feeling of having Joan's naked skin against hers.

Joan pressed a leg between Shirley's thighs and smiled slightly.

"Quite the excitable young lady, aren't we?" She whispered, coy and demure now that the heat had mostly faded from the room.

"Mmm. I'd apologize, but I'm sure you know that I'm not sorry," Shirley smiled.

Joan yawned, and pulled Shirley a bit tighter against her. It seemed that they weren't going to discuss it any further. Perhaps if they never talked about it, it wouldn't have to be strange. They could just be. Like they'd always been. Except more. Better. So bloody wonderful.

She planted a small kiss against Joan's forehead.

They both drifted off into a peaceful, sticky sleep.

* * *

_Well, there you have it friends. My very first attempt at Femslash. I hope you had as much fun as I did._

_xoxo_


End file.
